Compared to conventional illumination light source, semiconductor light emitting devices such as LEDs are small, have high efficiency and long lifetime as a light source. Recent market needs for saving energy and resource boosts the demand for light bulb shaped lamps using LEDs (hereafter simply referred to as “LED light bulb”) and lighting apparatuses including the LED light bulbs. Meanwhile, some manufacturers stop manufacturing incandescent light bulbs using filaments (filament coils).
For example, the patent literature 1 discloses a conventional LED light bulb reproducing the shape of conventional filament in an incandescent light bulb. In the LED light bulb disclosed in the patent literature 1, an optical fiber resembling the shape of a filament is housed in the globe, an end portion of the LED and the optical fiber are provided near the base, and the light emitted from the LED is coupled to the end portion of the optical fiber. With this configuration, the waves of the light emitted from the LED are guided to the inside of the optical fiber. This reproduces a state as if the filament emits light.